The circumference of a circle = \(\pi d\) or \(2\pi r\). Look at the sector of the circle shown below. To calculate the length of the arc, we need to know what fraction of the circle is shown.

3D shapes can be viewed from different points. Circles, sectors and arcs - Edexcel The circumference of a circle is its outside edge, and is the same distance from the centre at every point along ...